1. Field of the Invention
The present invention relates to an analog value adjustment circuit, a display driver circuit, and a method of adjusting an analog value.
2. Description of the Related Art
In order to absorb the process-parameter variation due to a manufacturing variation in semiconductor integrated circuits, a fuse circuit is sometimes used. Using the fuse circuit, analog values, such as a desired voltage value, current value, and oscillation frequency in a circuit, can be adjusted corresponding to the states set up by fuse elements that can be cut (blown out). For example, in the case of a display driver circuit which drives a display panel, such as a liquid crystal panel, a liquid crystal driving voltage with high precision is needed in order to carry out extremely fine picture expressions. However, it is difficult to generate an optimal liquid crystal driving voltage because of manufacturing variations or the like of the liquid crystal materials and the display driver circuit of the liquid crystal panel. Then, by generating a condition corresponding to a setup state (cutting state or non-cutting state) of the fuse elements using the fuse circuit and by carrying out fine-adjustments of the liquid crystal driving voltage corresponding to this state, an optimal picture expression can be realized.
However, a cutting (trimming) process of the fuse elements in an inspection process of semiconductor integrated circuits needs to be carried out on all semiconductor integrated circuits (semiconductor chips) on a wafer. For this reason, the cutting process of the fuse elements ends up taking a long time, thereby causing a problem of inviting an increase in the cost of the chip or the like.